Synthesis of SnTe Nanoplates with {100} and {111} Surfaces

TL;DR

This paper reports the synthesis of SnTe nanoplates with specific crystallographic surfaces to enhance topological surface states, and investigates their structural and electronic properties, including phase transitions and electron interactions.

Contribution

It introduces a method to synthesize SnTe nanoplates with controlled {100} and {111} surfaces, enabling selective access to topological surface states.

Findings

Nanoplates have lateral dimensions of tens of microns and thicknesses of hundreds of nanometers.

Structural phase transition from rock salt to rhombohedral observed at low temperatures.

High bulk carrier density leads to low-temperature resistance upturn indicating electron-electron interactions.

Abstract

SnTe is a topological crystalline insulator that possesses spin-polarized, Dirac-dispersive surface states protected by crystal symmetry. Multiple surface states exist on the {100}, {110}, and {111} surfaces of SnTe, with the band structure of surface states depending on the mirror symmetry of a particular surface. Thus, to access surface states selectively, it is critical to control the morphology of SnTe such that only desired crystallographic surfaces are present. Here, we grow SnTe nanostructures using vapor-liquid-solid and vapor-solid growth mechanisms. Previously, SnTe nanowires and nanocrystals have been grown.1-4 In this report, we demonstrate synthesis of SnTe nanoplates with lateral dimensions spanning tens of microns and thicknesses of a hundred nanometers. The top and bottom surfaces are either (100) or (111), maximizing topological surface states on these surfaces. Magnetotransport on these SnTe nanoplates shows high bulk carrier density, consistent with bulk SnTe crystals arising due to defects such as Sn vacancies. In addition, we observe a structural phase transition in these nanoplates from the high temperature rock salt to low temperature rhombohedral structure. For nanoplates with very high carrier density, we observe a slight upturn in resistance at low temperatures, indicating electron-electron interactions.